Kolleru Lake — Ramsar Wetland Between Krishna & Godavari & UPSC Geography Guide

Kolleru Lake is one of India's largest freshwater lakes, located in the state of Andhra Pradesh between the deltas of the Krishna and Godavari rivers. Designated as a Ramsar Wetland of International Importance in 2002 and as a Wildlife Sanctuary in 1999, Kolleru plays a critical ecological role as a natural flood buffer, a biodiversity hotspot for migratory birds, and a vital resource for local communities. However, the lake has faced severe degradation from aquaculture encroachment, pollution, and reduced water inflow.

For UPSC, Kolleru Lake is relevant to Geography (GS Paper I) for Indian lakes and drainage, and to Environment (GS Paper III) for wetland conservation, Ramsar Convention, and biodiversity.

Location and Physical Features

How Kolleru Functions

Kolleru Lake acts as a natural flood-balancing reservoir between the Krishna and Godavari river systems. During the monsoon, excess water from both river basins drains into Kolleru through 68 feeder channels. The lake absorbs this floodwater, preventing inundation of downstream areas. It then slowly releases water through the Upputeru channel into the Bay of Bengal.

This flood-buffering function makes Kolleru ecologically and economically critical for the densely populated coastal Andhra Pradesh.

Ecological Significance

Biodiversity

Kolleru Lake supports a rich ecosystem:

• Fish — historically one of India's most productive freshwater fisheries, supporting local fishing communities
• Migratory birds — the lake is a wintering ground for thousands of migratory birds from Siberia, Central Asia, and other regions
• Resident birds — large populations of pelicans, painted storks, herons, cormorants, and other waterbirds
• Aquatic vegetation — extensive beds of lotus, water hyacinth, and other macrophytes

Atapaka Bird Sanctuary

The Atapaka Bird Sanctuary (also called Kolleru Bird Sanctuary or Atapaka Sanctuary) is located within the Kolleru Lake ecosystem. It is particularly known for:

• Grey pelicans (Pelecanus philippensis) — one of the largest breeding colonies in India
• Painted storks (Mycteria leucocephala)
• Open-billed storks, darters, and night herons
• Peak bird arrivals occur between October and March

The sanctuary is a significant site for birdwatching and ornithological research.

Kolleru Wildlife Sanctuary

Kolleru Wildlife Sanctuary was declared in 1999 under the Wildlife Protection Act, 1972, covering an area of 308 sq km. The sanctuary encompasses the core lake area and surrounding wetlands. The notification aimed to provide legal protection against encroachment and pollution.

Ramsar Designation

Kolleru Lake was designated as a Wetland of International Importance under the Ramsar Convention on November 19, 2002 (Ramsar Site No. 1209). The designation recognises its value as:

• A critical habitat for migratory and resident waterbirds
• A flood-buffering wetland between two major river systems
• A freshwater ecosystem supporting significant biodiversity
• A resource for fisheries and local livelihoods

What is the Ramsar Convention?

Threats to Kolleru Lake

Aquaculture Encroachment

The most serious threat to Kolleru has been the explosive growth of commercial aquaculture (fish and prawn farming) within the lake bed:

• Starting in the 1970s-80s, entrepreneurs constructed thousands of fish ponds (tank bunds) within the lake
• By the early 2000s, an estimated 15,000-20,000 fish ponds had been built, occupying a significant portion of the lake bed
• These ponds fragmented the lake, reduced water holding capacity, blocked water flow, and discharged polluted wastewater
• The aquaculture boom was driven by high export demand for prawns and freshwater fish

Operation Kolleru (2006)

In response to the environmental crisis, the Andhra Pradesh government launched Operation Kolleru in January 2006:

• A massive demolition drive destroyed thousands of illegal fish ponds within the lake
• Over 1,700 fish ponds were demolished in the initial phases
• The operation was backed by Supreme Court and High Court orders directing the restoration of the lake
• It was one of India's largest wetland restoration operations

However, the operation was controversial — it displaced thousands of aquaculture workers and fishing families who depended on the fish ponds for their livelihoods.

Other Threats

Conservation Efforts

Comparison with Other Important Indian Lakes

UPSC Relevance

GS Paper Mapping

Key Points for Prelims

• Kolleru Lake is located in Andhra Pradesh between the Krishna and Godavari river deltas
• It is one of India's largest freshwater lakes with an area of approximately 245 sq km (expanding to 900+ sq km during floods)
• Designated as a Ramsar Wetland of International Importance in 2002
• Declared a Wildlife Sanctuary in 1999 under the Wildlife Protection Act
• The Atapaka Bird Sanctuary within Kolleru is known for grey pelicans and painted storks
• The lake functions as a natural flood buffer between the Krishna and Godavari systems
• Operation Kolleru (2006) demolished thousands of illegal aquaculture ponds within the lake
• Water drains from Kolleru into the Bay of Bengal through the Upputeru channel
• 68 feeder channels bring water into the lake, including Budameru and Tammileru
• Water hyacinth is a major invasive species threatening the lake ecosystem